CN110166357B

CN110166357B - Device supporting transparent interconnection protocol of multiple links and communication method thereof

Info

Publication number: CN110166357B
Application number: CN201810151332.8A
Authority: CN
Inventors: 卢诞春; 曹育诚
Original assignee: Accton Technology Corp
Current assignee: Accton Technology Corp
Priority date: 2018-02-14
Filing date: 2018-02-14
Publication date: 2021-09-10
Anticipated expiration: 2038-02-14
Also published as: CN110166357A

Abstract

A device supporting transparent interconnection protocol of multiple links and a communication method thereof are provided. The device supporting the transparent interconnection protocol of multilink comprises a memory, a processor and a communication interface. The memory includes a look-up table. The processor is coupled to the memory. The communication interface is coupled to the processor and comprises a trunk port and an access port for receiving a first packet. When the processor judges that the output port corresponding to the destination address of the first packet is a trunk port and does not have nickname information corresponding to the destination address according to the lookup table, the trunk port of the communication interface transmits the second packet. The second packet contains an enable field bit and the same payload data as the first packet. The invention effectively accesses and/or manages the non-multilink transparent interconnection device and reduces the probability of circularly forwarding the packet under the condition of simultaneously arranging the non-multilink transparent interconnection device and the multilink transparent interconnection device.

Description

Device supporting transparent interconnection protocol of multiple links and communication method thereof

Technical Field

The present invention relates to a device supporting transparent interconnection protocol and a communication method thereof, and more particularly, to a device supporting transparent interconnection protocol and a communication method thereof communicatively connected to a non-transparent interconnection network.

Background

Transparent Interconnection of Lots of Links (TRILL) technology is a standard of Internet Engineering Task Force (IETF) protocol. The transparent interconnection technology uses layer 3 routing technology to construct a relatively large layer 2 network cloud, so that when a host moves in the layer 2 network cloud, the host can be smoothly transferred to another node (such as a router) to continue to operate and provide services without changing the IP address setting.

The TRILL protocol defines the behavior of an Access Link (Access Link) to process ethernet frames transmitted to and from non-TRILL devices. TRILL protocol and defines the behavior of the backbone Link (Trunk Link) to handle incoming/outgoing frames containing TRILL headers (TRILL headers). However, the TRILL protocol does not define the behavior of the link connected between the TRILL device and the non-TRILL device.

That is, if the transparent interconnection device with non-multilink is disposed between the transparent interconnection devices with multilink, under the TRILL protocol, although the packet including the header of the transparent interconnection device with multilink can be transmitted through the transparent interconnection device with non-multilink, the packet cannot transmit data to the transparent interconnection device with non-multilink to access the transparent interconnection device with non-multilink, that is, the transparent interconnection device with non-multilink connected between the transparent interconnection devices with multilink cannot be accessed and/or managed under the TRILL protocol.

Therefore, how to transmit data to the non-multilink transparent interconnection device under the condition that the non-multilink transparent interconnection device and the multilink transparent interconnection device are simultaneously arranged so as to effectively access and/or manage the non-multilink transparent interconnection device is one of the problems to be improved in the field.

Disclosure of Invention

One aspect of the present invention is to provide an apparatus for supporting transparent interconnection protocol with multiple links. The device supporting the transparent interconnection protocol of multiple links comprises a memory, a processor and a communication interface. The memory includes a look-up table. The processor is coupled to the memory. The communication interface is coupled to the processor and comprises a trunk port and an access port for receiving a first packet. When the processor judges that the output port corresponding to the destination address of the first packet is a trunk port and does not have nickname information corresponding to the destination address according to the lookup table, the second packet is transmitted through the trunk port of the communication interface. The second packet includes an enable region bit. The first packet and the second packet include the same payload data.

In some embodiments, the processor is further configured to transmit a third packet via the trunk port of the communication interface when the first packet does not include a transparent multi-link header and the first packet is received by the access port of the communication interface, wherein the third packet is embedded in a transparent multi-link interconnect header and the third packet includes the same payload data as the first packet and the second packet.

In some embodiments, the processor further directs discarding of the second packet when the trunk port of the communication interface receives the second packet.

In some embodiments, the lookup Table further comprises a Forwarding Table (Forwarding Table) and a nickname Table.

In some embodiments, the lookup table further comprises destination address information, nickname information, trunk port information, and access port information.

In some embodiments, the enable field bit is a specific value included in the mac address of the second packet.

In some embodiments, the mac address of the second packet is a source address.

In some embodiments, the specific value is set in a bit set.

In some embodiments, the specific value is set to 1 for bit 2 of the group of bits.

Another aspect of the present invention is to provide a communication method for a network switch supporting transparent interconnection protocol with multiple links. The communication method comprises the following steps: receiving a first packet by a communication interface; the processor judges that an output port corresponding to the destination address of the first packet is a trunk port according to the lookup table, and transmits a second packet through the trunk port of the communication interface when nickname information corresponding to the destination address does not exist; wherein the second packet includes an enable field bit, and the second packet includes the same Payload data (Payload) as the first packet.

In some embodiments, when the first packet does not include a transparent multilink header and the first packet is received by an access port of the communication interface, the processor further transmits a third packet having the transparent multilink interconnect header through the trunk port of the communication interface, wherein the third packet has the same payload data as the first packet and the second packet.

In some embodiments, setting an enable field bit in the second packet sets a specific value at the mac address of the second packet.

In some embodiments, setting the specific value at the mac address of the second packet is setting the specific value in a bit set of the mac address.

In some embodiments, the 2 nd bit in the set of bits is set to 1 to set the specific value.

Therefore, according to the technical aspect of the present invention, embodiments of the present invention provide a device supporting a transparent interconnection protocol with multiple links and a communication method thereof, so as to effectively access and/or manage a transparent interconnection device with no multiple links and reduce the probability of a packet being forwarded in a loop under the condition that the transparent interconnection device with multiple links and the transparent interconnection device with multiple links are simultaneously disposed.

Drawings

In order to make the aforementioned and other objects, features, and advantages of the invention, as well as others which will become apparent, reference is made to the following description taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic diagram of a communication system according to some embodiments of the present disclosure;

FIG. 2 is a schematic diagram of a transparent interconnection device with multiple links according to some embodiments of the disclosure;

fig. 3 is a diagram illustrating an original frame according to some embodiments of the disclosure;

fig. 4 is a partial schematic diagram of a packet including an Enabled Local Bit according to some embodiments of the disclosure; and

fig. 5 is a flow chart of a communication method according to some embodiments of the disclosure.

Detailed Description

The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Elements and configurations in the specific illustrations are used in the following discussion to simplify the present disclosure. Any examples discussed are intended for illustrative purposes only and do not limit the scope or meaning of the invention or its illustrations in any way. Moreover, the present disclosure may repeat reference numerals and/or letters in the various examples, which are for purposes of simplicity and clarity, and do not in themselves dictate a relationship between the various embodiments and/or configurations discussed below.

The term (terms) used throughout the specification and claims has the ordinary meaning as commonly understood in the art, in the disclosure herein and in the claims, unless otherwise indicated. Certain terms used to describe the present disclosure will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the present disclosure.

As used herein, to "couple" or "connect" may mean that two or more elements are in direct physical or electrical contact with each other, or in indirect physical or electrical contact with each other, and "couple" or "connect" may also mean that two or more elements are in operation or act with each other.

It will be understood that the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections. These elements, components, regions, layers and/or regions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. As used herein, the word "and/or" includes any combination of one or more of the associated listed items. Reference to "and/or" in this document refers to any one, all, or any combination of at least one of the listed elements.

Please refer to fig. 1. Fig. 1 is a schematic diagram of a communication system 100. The communication system 100 includes a plurality of NON-transparent interconnection of lots of links (NON-TRILL) devices 130A to 130F, a plurality of transparent interconnection of lots of links (TRILL) devices 110A to 110D, and

servers

150A, 150B. The transparent interconnection devices 110A to 110D are communicatively connected to each other via a portion of the plurality of non-transparent interconnection devices 130A to 130F, respectively. The

servers

150A, 150B are communicatively connected to one of the plurality of transparent interconnection devices 110A to 110D, respectively.

A transparent interconnection device is a device that supports a transparent interconnection protocol, such as a switch, router, wireless access point, or equivalent. A non-multilink transparent interconnect device is a device that does not support the multilink transparent interconnect protocol, such as a switch, router, wireless access point, or equivalent thereof.

In some embodiments, the non-multilink transparent interconnection devices 130A to 130F, the multilink transparent interconnection devices 110A to 110D, and the

servers

150A, 150B each have a media access control Address (MAC Address).

In some embodiments, the transparent interconnection devices 110A to 110D respectively include an Access Port (Access Port) and/or a Trunk Port (Trunk Port), wherein the Access Port is a Port capable of transmitting packets without transparent interconnection header, and the Trunk Port is a Port capable of transmitting and receiving packets with transparent interconnection header.

Taking fig. 1 as an example, the transparent interconnection apparatus 110A to 110D respectively include trunk ports 114a1, 114a2, 114B1, 114B2, 114C1, 114C 2114D 1 and 114D 2. The

multiple interconnect devices

110A and 110D include

access ports

112A and 112D, respectively, for receiving packets transmitted from the

servers

150A and 150B, respectively. The multilink transparent interconnection devices 110A to 110D each include a look-up table (look-up table). The lookup Table may contain a forwarding Table (forwarding Table) and a Nickname Table (Nickname Table). In one embodiment, the lookup table may also be a lookup table that includes forwarding table and nickname table information integrated into one.

The forwarding table includes a media access Address (MAC Address) and corresponding port information, and is used to provide an output port for searching a corresponding packet destination Address. The nickname table contains the media access addresses of the multilink transparent interconnection devices 110A to 110D and their corresponding nickname information. For example, the nickname information of the nickname table in the transparent interconnection device 110A includes a nickname B of the transparent interconnection device 110B, a nickname C of the transparent interconnection device 110C, and a nickname D of the transparent interconnection device 110D.

According to the lookup table, the transparent interconnection device 110A to 110D can know which port the packet needs to be output through, and determine a nickname corresponding to the packet destination address when the output port is a trunk port, or determine that there is no corresponding nickname information. In this embodiment, if the media access address in the lookup table corresponds to the non-corresponding nickname information, it means that the media access address is a non-multi-link transparent interconnection device.

Referring to fig. 2, which is a schematic diagram of a transparent interconnection device 110 according to some embodiments of the disclosure, the transparent interconnection device 110 may be used to represent the transparent interconnection devices 110A to 110D shown in fig. 1. The transparent interconnection device 110 includes a memory 117, a processor 118, and a communication interface 119. The memory 117 is coupled to the processor 118, and the processor 118 is coupled to the communication interface 119. The memory 117 contains a lookup table, and the communication interface 119 includes an access port and a backbone port as shown in FIG. 1.

Please refer to fig. 1 and fig. 2 together. In the following, taking the case that the server 150A wants to transmit data to the transparent interconnection apparatus without multilink 130E as an example, how the transparent interconnection apparatus without multilink connected to the backbone port of the transparent interconnection apparatus with multilink receives data transmitted by the server is described, and it is assumed that the transparent interconnection apparatuses with multilink 110A to 110D have previously obtained various path information according to various known methods, and a lookup table is established accordingly. When the server 150A transmits an original Frame (Native Frame) or original packet containing payload data to the transparent interconnection device 110A, the transparent interconnection device 110A receives the original Frame or original packet through the communication interface 119, and the internal processor 118 can determine that the original Frame or original packet is incoming through the access port 112A, i.e. determine that the original Frame or original packet is received by the access port. Then, the processor 118 of the transparent interconnection device 110A queries the lookup table according to the destination address of the original frame or the original packet to determine whether the data in the original frame or the original packet is sent out through the trunk port. When the processor 118 of the transparent interconnection device 110A determines that the output port of the original frame or the original packet is the trunk port 114a2 and the trunk port 114a2 is the trunk port, the processor 118 of the transparent interconnection device 110A further determines whether the nickname information corresponding to the destination address of the original frame or the original packet exists in the lookup table.

In this example, since the output port is a trunk port and the destination address is the non-multilink transparent interconnection device 130E, the destination address in the lookup table corresponds to the non-corresponding nickname information, and therefore, the processor 118 of the multilink transparent interconnection device 110A does not have the corresponding nickname information according to the result of the lookup table by the destination address. In this case, the processor 118 of the transparent interconnection device 110A sends a packet including an Enabled Local Bit (Enabled Local Bit) through the communication interface 119 of the transparent interconnection device 110A. Since the packet containing the enable field bits does not have the transparent interconnect with multilink header, the transparent interconnect with unlink device 130E will receive the packet with the enable field bits and retrieve the data carried by the packet. In an embodiment, according to the transparent interconnection protocol, when the lookup table does not have the corresponding Nickname information, the transparent interconnection header with the multilink is embedded in the original frame, and the root routing bridge Nickname is filled in the Egress routing bridge Nickname field (Egress RBridge Nickname), and the packet with the transparent interconnection header with the multilink is sent out from the trunk port. Therefore, in implementation, the trunk port will transmit the packet with the enable field bit and the packet with the transparent interconnection header of multilink, but the transparent interconnection device 130E does not directly forward the packet with the transparent interconnection header of multilink when receiving the packet with the transparent interconnection header of multilink because it does not support the transparent interconnection protocol of multilink, however, the packet with the enable field bit can be accessed to obtain the data sent by the server 150A. In this manner, the server 150A can access or manage the non-multilink transparent interconnection device 130E accordingly.

In the following, a case where the server 150A wants to transmit data to the non-multilink transparent interconnection device 130F is taken as an example, and it is assumed that the multilink transparent interconnection devices 110A to 110D have established the lookup table. In this example, since the output port is a trunk port and the destination address is the transparent interconnection device 130F, the destination address in the lookup table has corresponding nickname information, and therefore, the processor 118 of the transparent interconnection device 110A according to the result obtained by searching the lookup table by the destination address corresponds to the nickname information as the nickname C. In this case, according to the transparent interconnection protocol, when the lookup table has corresponding Nickname information, the transparent interconnection header with multiple links is embedded in the original frame, and the exit route bridge Nickname field (Egress RBridge Nickname) is filled with the Nickname C of the transparent interconnection device 110C, and the trunk port 114a2 sends out the packet with the transparent interconnection header with multiple links.

Then, after the transparent interconnection device 110C receives the packet containing the transparent interconnection header via the trunk port 114C1, the processor 118 of the transparent interconnection device 110C determines the output port corresponding to the packet destination address as the trunk port 114C2 from the lookup table of the transparent interconnection device 110C. As in the previous example, at this time, the transparent interconnection device 130F without multiple links will not have corresponding nickname information in the lookup table, the processor 118 of the transparent interconnection device 110C determines that the packet destination address corresponds to the nickname information without corresponding nickname information, and the processor 118 of the transparent interconnection device 110C is further configured to send out the packet including the enabled area bit through the communication interface 119 of the transparent interconnection device 110C. As in the previous example, the root routing Nickname is filled in the Egress routing bridge Nickname field (Egress RBridge Nickname) of the packet multilink transparent interconnection header, and then sent out through the communication interface 119 of the multilink transparent interconnection device 110C.

Through the above implementation, if the packet is to be transmitted to the transparent interconnection device with no multiple links on the trunk port, the packet with the enabled area bit will be transmitted, and the transparent interconnection device with no multiple links can access the packet with the enabled area bit to obtain the data sent by the server 150A. In this manner, the server 150A can access or manage the non-multilink

transparent interconnection device

130E or 130F connected to the backbone port.

The content of the original frame and the packet including the enabled field bit will be described in detail with reference to fig. 3 to 4.

Fig. 3 is a diagram illustrating an original frame 300 according to some embodiments of the disclosure. The original frame 300 does not include a multilink transparent interconnect header, nor does the original frame 300 include an enable field bit. Referring to fig. 3, in some embodiments, the original frame 300 includes a Cyclic Redundancy Code (CRC), a Payload data (Payload), a Type/Length (Type/Length), and an address Header (MAC Header).

In some embodiments, the address Header (MAC Header) includes a destination address (MAC DA), a source address (MAC SA), a virtual network Tag (VLAN Tag). The original frame 300 shown in fig. 3 is only for illustration and the disclosure is not limited thereto.

In some embodiments, a packet (not shown) including a transparent interconnection Header (TRILL Header) and an Outer Header (Outer MAC Header) may be generated by adding the transparent interconnection Header (TRILL Header) and the Outer Header to the original frame 300 illustrated in fig. 3.

Fig. 4 is a diagram of a structure of a group of bits (First Octet) in a medium access address. In some embodiments, the packet 400 including the enable field bit has the same Format (Format) as the original frame 300 of fig. 3, only the bits of the mac address field in the packet include a specific value, which is used to identify the packet as a packet including the enable field bit. In one embodiment, as shown in FIG. 4, the first bit set in the media access address (MAC SA) includes bits b 0-b 7, with the particular value being when b1 has a value of 1, thereby indicating that the packet includes an Enable _ Segment bit. In this embodiment, the MAC address is a source address. In other embodiments, the specific value may be a value in any one of the bits and/or any one of the bits in the mac address. In some embodiments, the packet 400 including the enable field bit as illustrated in fig. 4 may be generated by setting the value of the first bit b1 of the source address (MAC SA) in the original frame 300 illustrated in fig. 3 to 1.

In addition, when the transparent interconnection device 110A to 110D receives the packet containing the enable field bit, the processor 118 of the transparent interconnection device 110A to 110D discards the packet containing the enable field bit, so as to ensure that the non-transparent interconnection device can not only receive the packet, but also not cause the packet to be circularly forwarded to affect the network transmission performance.

Through the manner, the embodiment of the scheme can effectively access and/or manage the non-multilink transparent interconnection device under the condition that the non-multilink transparent interconnection device and the multilink transparent interconnection device are arranged at the same time. In addition, because the packet containing the enable field bit is discarded after being received by the transparent interconnection device, the probability of the packet being circularly forwarded can be reduced.

Please refer to fig. 5. Fig. 5 is a flow chart of a communication method 500 according to some embodiments of the disclosure. In some embodiments, the communication method 500 is applied to the multilink transparent interconnection devices 110A to 110D. As shown in fig. 5, the communication method 500 includes a plurality of steps S510, S530, S532, and S534.

In step S510, a packet is received. For example, please refer to fig. 1, fig. 2 and fig. 5 together. The transparent interconnection device 110A can receive the packet, the original packet or the original frame from the server 150A through the communication interface 119.

In step S530, it is determined whether the output port corresponding to the destination address of the packet is a trunk port and whether there is no nickname information corresponding to the destination address according to the lookup table of the transparent interconnection device with multilink. If it is determined that the output port corresponding to the destination address of the packet is the trunk port and there is no nickname information corresponding to the destination address, step S532 is executed. On the contrary, if it is determined that the output port corresponding to the destination address of the packet is the trunk port and has the nickname information corresponding to the destination address, step S534 is executed.

For example, please refer to fig. 1, fig. 2 and fig. 5 together. If the transparent interconnection device 110A receives the original frame transmitted by the server 150A through the access port 112A, the processor 118 of the transparent interconnection device 110A determines whether the output port corresponding to the destination address of the original frame is a trunk port and whether there is no nickname information corresponding to the destination address of the original frame according to the lookup table of the transparent interconnection device 110A.

In step S532, a packet including the enable field bit is transmitted. For example, please refer to fig. 1, fig. 2 and fig. 5 together. If the transparent interconnection device 110A receives the packet transmitted by the server 150A through the access port 112A, the processor 118 of the transparent interconnection device 110A determines that the output port corresponding to the destination address of the original packet is the trunk port 114a2 and does not have nickname information corresponding to the destination address of the original packet according to the lookup table of the transparent interconnection device 110A, and the processor 118 of the transparent interconnection device 110A transmits the packet including the enabled area bit through the trunk port 114a2 of the communication interface 119. It should be noted that, in this step, a packet including a multilink transparent interconnection header is further sent according to the multilink transparent interconnection protocol, and an Egress Nickname field of the header is filled in the root routing bridge Nickname.

In step S534, a packet including the multilink transparent interconnect header is transmitted. For example, please refer to fig. 1, fig. 2 and fig. 5 together. If the transparent interconnection device 110A receives the packet transmitted from the server 150A through the access port 112A, the processor 118 of the transparent interconnection device 110A determines that the output port corresponding to the destination address of the packet is not a trunk port and has Nickname information corresponding to the destination address, and the transparent interconnection device 110A transmits the packet including a transparent interconnection header with Egress Nickname field corresponding to the destination address through the communication interface 119.

As can be seen from the foregoing embodiments, the embodiments of the present disclosure can effectively access and/or manage the non-multilink transparent interconnection apparatus under the condition that the non-multilink transparent interconnection apparatus and the multilink transparent interconnection apparatus are simultaneously disposed. In addition, when the multilink transparent interconnection device receives the packet containing the enable area bit, the packet containing the enable area bit is discarded, so that the probability of cyclic forwarding of the packet can be reduced.

In some embodiments, the

servers

150A, 150B may be circuits or other equivalent devices that have the function of storing, computing, reading data, receiving signals or information, transmitting signals or information, and the like. That is, through the above steps, the packet destined to the non-multilink transparent interconnect device 130F can be successfully transmitted from the transparent interconnect device 110A to the non-multilink transparent interconnect device 130F.

In some embodiments, the processor 118 included in the transparent interconnection device 110A to 110D may be a circuit having functions of storing, calculating, reading data, receiving signals or information, transmitting signals or information, or other equivalent elements, including a Central Processing Unit (CPU), a processor chip, or the like.

In some embodiments, the memory 117 included in the transparent interconnection device 110A-110D may be a circuit or other equivalent device that can store data, read data, receive signals or information, transmit signals or information, and the like, including a dynamic random access memory, a static random access memory, a flash memory, and the like.

In some embodiments, the transparent interconnection device 130A to 130F further comprises a processor (not shown), a memory (not shown), and a communication interface (not shown).

Additionally, the above illustration includes exemplary steps in sequential order, but the steps need not be performed in the order shown. It is within the contemplation of the disclosure to perform these steps in a different order. Steps may be added, substituted, changed in order, and/or omitted as appropriate within the spirit and scope of embodiments of the present disclosure.

Although the present disclosure has been described with reference to the above embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the disclosure, and therefore, the scope of the disclosure is to be determined by the appended claims.

Claims

1. An apparatus for supporting a transparent interconnection protocol with multiple links, comprising:

a memory, the memory including a lookup table;

a processor coupled to the memory; and

a communication interface, coupled to the processor, including a trunk port and an access port, for receiving a first packet;

when the processor judges that an output port corresponding to a destination address of the first packet is the trunk port and does not have nickname information corresponding to the destination address according to the lookup table, the trunk port of the communication interface transmits a second packet;

wherein the second packet includes an enable field bit and includes the same Payload data (Payload) as the first packet;

wherein the lookup Table further comprises a Forwarding Table (Forwarding Table) and a nickname Table.

2. The apparatus of claim 1, wherein when the first packet does not include a transparent multilink header and the first packet is received by the access port of the communication interface, the processor is further configured to transmit a third packet via the trunk port of the communication interface, wherein the third packet is embedded in a transparent multilink interconnect header and the third packet includes the same payload data as the first packet and the second packet.

3. The apparatus of claim 1 wherein the processor further directs the second packet to be discarded when the trunk port of the communication interface receives the second packet.

4. The apparatus of claim 1, wherein the lookup table further comprises destination address information, nickname information, trunk port information, and access port information.

5. The apparatus of claim 1 wherein the enable field bit is a specific value included in the MAC address of the second packet.

6. The apparatus of claim 5 wherein the MAC address of the second packet is a source address.

7. The apparatus of claim 5, wherein the specific value is set in a bit set.

8. The apparatus of claim 7, wherein the specific value is set to 1 for bit 2 of the set of bits.

9. A communication method, adapted for a network switch supporting a transparent interconnection protocol with multiple links, comprising:

receiving a first packet by a communication interface;

when a processor judges that an output port corresponding to the destination address of the first packet is a trunk port and nickname information corresponding to the destination address does not exist according to a lookup table, a second packet is transmitted by the trunk port of the communication interface after an enabling area bit is set in a second packet; wherein the second packet and the first packet comprise the same Payload data (Payload);

10. The method of claim 9 wherein the processor further transmits a third packet with the transparent interconnection header via the backbone port of the communication interface when the first packet does not include a transparent interconnection header and the first packet is received by an access port of the communication interface, wherein the third packet has the same payload data as the first packet and the second packet.

11. The method of claim 9 wherein the setting of an enable field bit in the second packet is setting a specific value at the MAC address of the second packet.

12. The method of claim 11 wherein the setting the specific value at the MAC address of the second packet is setting the specific value in a set of bits of the MAC address.

13. The method of claim 12, wherein bit 2 of the set of bits is set to 1 to set the specific value.